Problem: Reduce to lowest terms: $ \dfrac{7}{9} \div - \dfrac{3}{5} = {?}$
Dividing by a fraction is the same as multiplying by the reciprocal of the fraction. The reciprocal of $- \dfrac{3}{5}$ is $- \dfrac{5}{3}$ Therefore: $ \dfrac{7}{9} \div - \dfrac{3}{5} = \dfrac{7}{9} \times - \dfrac{5}{3} $ $ \phantom{ \dfrac{7}{9} \times - \dfrac{5}{3}} = \dfrac{7 \times -5}{9 \times 3} $ $ \phantom{ \dfrac{7}{9} \times - \dfrac{5}{3}} = \dfrac{-35}{27} $